McGeechan, a three-time British Lions coach and one of rugby's most respected gurus, said he doubted there was a problem with drugs after World Cup organisers announced tests for a new designer steroid.

"I'd be very surprised if there was any drug involvement in our game," McGeechan said from Scotland's training base in Cronulla.

"We're monitored very closely, but rugby's just not part of that culture.

"I think the worst we've had in the past is the wrong cough mixtures."

McGeechan was responding to a statement from the International Rugby Board on Thursday that testing for the new designer steroid tetrahdyrogestinone (THG) will begin next week at the Rugby World Cup.

The drugs scandal is threatening to unmask dozens of athletes in track and field and other sports.

The conclusion is clear - the cheaters are keeping two steps ahead of testing

France flanker Olivier Magne

Rugby World Cup organisers said the test for THG will be applied to all new samples collected and may extend to samples already collected as part of the tournament anti-doping program.

But not everyone is as confident as McGeechan that rugby union will escape with its image intact.

Ireland coach Eddie O'Sullivan said: "There are people who will abuse drugs to get what they want and get where they want.

"It is a collision sport where power and strength are critical so unfortunately, like any other power sport in the world, I think we would struggle with drugs in rugby."

France flanker Olivier Magne added: "The conclusion is clear - the cheaters are keeping two steps ahead of testing."

Last month 19 players from a Romanian First Division club were banned for two years for drugs offences, while another 19 players from a junior Welsh club were suspended for refusing to take tests.